Elastomer composition and pressure-sensitive adhesives made by using same

Abstract

A process for the production of a pressure-sensitive adhesive composition is provided comprising (1) forming an elastomer composition by mixing in the form of a solution, 33.5 to 95% by weight of an aromatic vinyl-isoprene block copolymer (a) having two or more poly(aromatic vinyl) blocks, 0 to 47.5% by weight of an aromatic vinyl-isoprene diblock copolymer (b), and 5 to 33% by weight of isoprene homopolymer (c) having a weight average molecular weight of 20,000 to 100,000, wherein the elastomer composition has a content of aromatic vinyl monomer unit of 14 to 50% by weight, (2) separating the elastomer composition from the solvent, (3) drying the elastomer composition, and (4) blending a petroleum resin with the elastomer composition made by steps (1)-(3), wherein the amount of the petroleum resin is 10 to 500 parts by weight based on 100 parts by weight of the elastomer composition.

1. A process for producing a pressure-sensitive adhesive composition, said process comprising the following steps:
 (1) making an elastomer composition by mixing in the form of a solution, 
 33.5 to 95% by weight of an aromatic vinyl-isoprene block copolymer (a) having two or more poly(aromatic vinyl) blocks, 
 0 to 47.5% by weight of an aromatic vinyl-isoprene diblock copolymer (b), and 
 5 to 33% by weight of isoprene homopolymer (c) having a weight average molecular weight of 20,000 to 100,000, the total amount of the components (a), (b) and (c) being 100% by weight, 
 wherein the elastomer composition has a content of aromatic vinyl monomer unit of 14 to 50% by weight based on the total amount of the components (a), (b) and (c), 
 (2) separating the elastomer composition from the solvent, 
 (3) drying the elastomer composition, and 
 (4) blending a petroleum resin with the elastomer composition made by steps (1)-(3), wherein the amount of the petroleum resin is 10 to 500 parts by weight based on 100 parts by weight of the elastomer composition. 
 
     
     
       2. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the weight average molecular weight of the aromatic vinyl-isoprene block copolymer (a) is 120,000 to 1,200,000. 
     
     
       3. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the content of aromatic vinyl monomer unit in the aromatic vinyl-isoprene block copolymer (a) is 17 to 50% by weight. 
     
     
       4. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the weight average molecular weight of the aromatic vinyl-isoprene diblock copolymer (b) is 60,000 to 250,000. 
     
     
       5. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the content of aromatic vinyl monomer unit in the aromatic vinyl-isoprene diblock copolymer (b) is 16 to 55% by weight. 
     
     
       6. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the content of 3,4 bonded isoprene unit of the isoprene homopolymer component (c) is 20% by weight or less. 
     
     
       7. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the weight average weight of the isoprene homopolymer (c) is 25,000 to 95,000. 
     
     
       8. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the weight average weight of the isoprene homopolymer (c) is 30,000 to 90,000. 
     
     
       9. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the composition contains 1 to 40% of the copolymer (b). 
     
     
       10. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the composition contains 2 to 30% of the copolymer (b). 
     
     
       11. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the composition contains 10 to 31.5% of the isoprene homopolymer (c). 
     
     
       12. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the composition contains 15 to 30% of isoprene homopolymer (c). 
     
     
       13. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the composition has a content of aromatic vinyl monomer unit of 15 to 35% by weight based on the total amount of the components (a), (b) and (c). 
     
     
       14. The process for producing the pressure-sensitive adhesive composition according to  claim 1 , wherein the composition has a content of aromatic vinyl monomer unit of 17 to 25% by weight based on the total amount of the components (a), (b) and (c). 
     
     
       15. A process for producing the pressure-sensitive adhesive label which comprises the step of applying a pressure-sensitive adhesive composition made by the process of  claim 1  to a backing support.